Add FM Playback Volume for Allwinner A10 and Allwinner A20.
Add FM Left, FM Right, FM Playback Switch for Allwinner A10 and
Allwinner A20.

Signed-off-by: Danny Milosavljevic <dannym@scratchpost.org>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Mark Brown <broonie@kernel.org>